Art of obtaining gasoline hydrocarbons



"Se t. 20, 1932. E l 1,877,914

ART OF OBTAINING GASOLINE HYDROCARBONS I Filed March 21, 1928 24 2 T I a, STRJPPJA G QS'TJLL Patented Sept. 20, 1932 UNITED STATES WARREN K.

PATENT OFFICE LEWIS, OF NEWTON, MASSACHUSETTS, ASSIGrNOR TO STANDARD OI'I: DEVELOPMENT COMPANY, A CORPORATION OF DELAWARE ART OF OBTAINING GASOLINE HYDROCARBONS Application filed March 21, 1928. Serial No. 263,410.

The present invention relates to the art of recovering condensible constituents from hydrocarbon gas and more specifically to an apparatus for the recovery of normally liquid hydrocarbons from natural gas, still gas, or

the like. The present application is a continuation in part of my former application,

Serial No. 616,777, filed February 3, 1923.

My apparatus and its operation will be fully understood from the following description and the drawing in which- Fig. 1 represents semi-diagrammatically a vertical section of one form of apparatus contemplated in the invention; and

Fig. 2 is a similar view of a modification; both Figures being broken for accommodation to the limits of the drawing.

In Fig. v1 of the drawing, the reference character 1 designates a cooling apparatus 29 afi'ording contact between gas and accumulated liquid, for example a tower of the type containing a series of plates with bell-caps and overflows. Arranged in the upper end of the tower is a suitable cooling means, as a coil 2 having an inlet and outlet 3, and 4 for a cooling fluid. A gas inlet pipe 5 connects into the bottom or lower portion of the tower, and a gas outlet 6 with a controlling valve 7 is provided at the top.

A gas carrying constituents to be recovered, for ex ample casing head gas or other natural gas or tail gas from stills, is introduced hot and under pressure, into the tower, by the inlet 5. Cooling is effected in a gradually progressive manner as the gas proceeds, the

constituents which condense along in the tower flowing down in intimate contact with the rising gas and themselves efi'ecting a graduated cooling action upon it, also certain light- 40 er constituents re-vaporizing progressively abstract heat, and so the gas is progressively cooled to the top of the tower. In this manner a high eiiiciency is realized in the cooling and in the obtaining ofjust the constituents desired. Pressure is maintained in the tower, for example in making natural gas gasoline a tower pressure of 7 5-200 lbs. per square inch is ordinarily suitable but this may be varied with the gas used. The condensate reaching the bottom of the tower is taken off by pipe naphtha absorbent, which is drawn ofl at the pipe 19 returns the stripped oil through a 8, and the stripped gas leaves the system through the pressure controlling valve 7.

Where desired, operations may be carried on in the presence of-an absorbent liquid, this being introduced into the top of the tower as at 9, so as to distribute and flow down countercurrent to the gas. In using naphtha for instance as the liquid, the desired constituents separated from the gas are carried with the bottom of the tower through pipe 8. In accordance as, lighter or heavier naphtha is used and the amount fed is proportioned, lighter or heavier casinghead stock may be made, or even a finished gasoline may be prepared. INhen using an absorbent having boiling points above the gasoline range, as for instance, mineral seal oil, which is miscible with the condensed constituents of the gas and is substantially non-volatile under the conditions imposed, such oil may be run down through the tower and through a stripping still to remove the constituents picked up from the gas. For such usage. the apparatus shown in Fig. 2 is advantageous. The tower 75 10 of suitable construction, for example as of the type already mentioned, is provided with a gas inlet pipe 15 at the lower portion of the tower, and a gas outlet 16 with a pressure controlling valve 17 is provided at the A pipe 18 leads to a stripping still S of any usual or preferred construction, and a coil 20 and pipe 21 to discharge into the top of the tower.' A cooling box 22 is interposed to insureadequate reduction in temperature before the oil enters the tower. The gas to be treated enters by pipe-15 and flows up countercurrently to the absorber liquid, which having been suitably cooled flows down to cool the rising gas, and additionally, as in the first case, condensates forming flow down and also eiiect a graduated temperature exchange with the gas, with a total result of progressively cooling the gas and absorblng the desired constituents. In distinction to prior methods of rectification in the absence ofabsorption liquid, I-have designated the 100 novel method described herein as absorptive rectification.

The stripped gas leaves the system at valve 17, and the absorber oil with retained constituents flows out by pipe 18 to the stripping still where the gasoline constituents are taken off and the hot stripped absorber oil is returnedthrough the pipe 19, and coil 20. A by-pass 23 with controlling valve 24 is provided and the quantity of hot oil to the coil 20 is regulated as desired by the valves 24 and 25 to secure proper vaporization in the tower; and the cooling box 22 conditions the temperature of the oil for its entrance into the top of the tower. Where desired, cooling coils 11 having inlets and outlets for cooling fluid may be provided in the upper part of the tower.

While I have described the invention with claim all inherent novelty as. broadly as the prior art permits.

I claim:

1. Apparatus of the character described, which comprises a tower containing means for providing contact between gas and liquid, an inlet for gas at the lower portion of said tower, an outlet for stripped gas at the top of the tower, means for maintaining pressure in the tower, cooling coils in the upper portion of the tower, a coil for liquid in the lower portion of the tower, a cooling box, a

\ ing surfaces within the upper portion of the connecting pipe from said coil, through the cooling box to the top of the tower, and a stripping still communicating with the loottom of the tower to receive liquid therefrom and communicatin with the inlet of the coil.

2. Apparatus o the character described, which comprises atower, means therein providing intimate contact between gas and liquid, means for admitting gas to be strifi ed into the lower portion of the tower, a coil for circulating hot fluid in the lower portion of the tower an outlet for stripped gas adjacent the top of the tower, means for maintaining superatmospheric pressure in the tower, cooltower for maintaining a substantially lower temperature than that in the bottom of the tower, means for conducting liquid from the C011 exteriorly of the tower into the upper portion of the tower, and a stripping still communicating wit-h the bottom of the tower to receive liquid therefrom and communicating with the coil.

3 Apparatus of the character described, wh ch comprises a tower, means therein pro vidlng mtimate contact between as and liquid, means for admit-ting gas to e stripped.

into the lower portion of the tower, a coil for circulating hot fluid in the lower portion from the coil exteriorly of the tower into the upper portion of the tower, a stripping still communicating with the bottom of the tower to receive liquid therefrom and com municating with the coil, and a by-pass linedisposed exteriorly of the tower communicating with the inlet and discharge of the coil.

WARREN K. LEWIS. 

